The present invention relates to safety devices for pressure cooking appliances having bayonet closures. More particularly, the present invention relates to implementing rotary abutment means for preventing rotation of the lid relative to the pan in a direction corresponding to closing the appliance, and means for locking the lid relative to the pan under drive from control means suitable for being actuated by the user, and for taking up at least one locking position in which relative rotation between the lid and the pan is prevented.
The present invention also relates to a safety device for a pressure cooking appliance with a bayonet closure and comprising:
a pan having pan ramps;
a lid having lid ramps;
rotary abutment means for preventing the lid rotating relative to the pan, placed so that in the closed position the lid ramps engage the pan ramps, the lid and the pan then being prevented from rotating in the direction of rotation that corresponds to closing the appliance;
locking means for locking the lid relative to the pan, the locking means being mounted to move on the appliance under drive from control means suitable for being actuated by the user between at least one unlocking position enabling the appliance to be opened and at least one locking position in which relative rotation between the pan and the lid is prevented; and
a pressure indicator mounted to move freely on the lid between a high, leakproof position and a low, leakage position, depending on the pressure that exists within the appliance.
Still more particularly, the present invention relates to a xe2x80x9cbayonetxe2x80x9d type pressure cooker fitted with an opening safety device.
As a general rule, the locking/unlocking devices of xe2x80x9cbayonetxe2x80x9d type pressure cookers implement locking principles that make use of alignment between a handle of the pan and a handle of the lid to trigger displacement of a latch, displacement generally being along a radial direction relative to the axis of symmetry of the pan. Such a principle is disclosed, e.g. in French Patent No. 2,484,817 in the name of the Applicant.
French Patent No. 2,484,817 describes a pressure cooker whose handle includes a member for locking the lid relative to the pan, which member extends substantially radially relative to the wall of the pan and is mounted to be movable in a radial direction. The locking member is provided with an orifice that makes it possible, in the closed position, to pass an operating valve freely therethrough when the lid is properly closed. Incomplete closure will lead to the valve being out of alignment with the opening provided in the sliding locking member, thereby preventing any rise of pressure inside the pressure cooker, as a safety measure.
Such systems are in widespread use on xe2x80x9cbayonetxe2x80x9d type pressure cookers, with that known locking/unlocking principle being suitable for implementation in numerous configurations, e.g. making the locking member act either directly or indirectly when the pressure cooker is put under pressure. Furthermore, there exist numerous configurations of openings depending on the level of safety provided by the design, in association with other safety devices, e.g. making use of one or more operating valves and/or deformation of a sealing gasket.
Such systems provide the user of a pressure cooker with a level of safety that is universally recognized, but at the same time give rise to various drawbacks during design and manufacture.
Thus, it turns out that the design of pressure cookers using locking of the above type requires compliance with a chain of multiple design dimensions, which is difficult to achieve. This chain of dimensions comprises a large stack of components such as the pan, the fixing pin for the handles, the locking member, the handle of the lid, the lid, the compression of the gasket, etc. Industrially, and particularly during manufacture, this gives rise to major dimensional constraints on the manufacturer, and that constitutes a significant industrial drawback. In addition, on that type of pressure cooker, there is only one single position for relative locking between the lid and the pan.
Locking/unlocking devices for pressure cookers are also known which implement principles of locking and safety on opening that imply a certain amount of simplification. Thus, French Patent No. 1,052,130 describes a principle of locking and safety on opening implementing means for locking the lid relative to the pan, which means extends substantially parallel to the wall of the pan and is vertically movable. The locking means in this case is mounted on the lid and is associated with control means, in association with a rated operating valve. The locking means is designed to penetrate into a cavity provided in the handle of the appliance to lock the pressure cooker, while the rated operating valve is simultaneously put into action in its seat by its compression spring.
Apart from the relatively rudimentary level of safety that it provides, such a system suffers from the drawback of still requiring compliance with a considerable chain of design dimensions, and of providing an insufficient level of safety. It is possible to open the appliance while a certain amount of excess pressure still exits in the pressure cooker, since unlocking is performed simultaneously when the operating valve is freed. The level of safety is therefore not optimal.
Consequently, the objects of the present invention seek to remedy the various drawbacks enumerated above, and to propose a novel opening safety device for a pressure-cooking appliance having a bayonet closure, that has improved safety and improved handling.
Another object of the present invention is to provide a novel safety device that allows the appliance to be easily cleaned, and that allows the appliance to be cleaned in a dishwasher.
Another object of the present invention is to propose a novel safety device that is particularly simple to implement and make.
Another object of the present invention is to propose a novel safety device that is simpler to manipulate, and that provides an improved level of safety.
A further object of the present invention seeks to propose a novel safety device that is particularly robust and insensitive.
In accordance with the present invention, these and other objections have now been realized by the invention of a pressure cooker comprising a pan including a pan ramp, a lid including a handle and a lid ramp cooperative with the pan ramp to provide a bayonet closure, whereby the pan and the lid can move from an open position wherein the pan ramp and the lid ramp are not cooperatively engaged to a closed position wherein the pan ramp and the lid ramp are cooperatively engaged by rotating the lid in a first direction with respect to the pan, rotary abutment means for preventing further rotation of the lid relative to the pan in the first direction when the pan and the lid are in the closed position, a lock mechanism for locking the lid relative to the pan, a controller for controlling the lock mechanism, the controller adapted to move the lock mechanism between at least one unlocking position wherein the lid can be removed from the pan and at least one locking position wherein the lid cannot be removed from the pan, a pressure indicator mounted with respect to the lid and movable between a first position wherein pressure within the pressure cooker cannot leak therethrough and a second position wherein the pressure can leak therethrough, and a unitary assembly mounted on the lid independent of the handle, the pressure indicator, the controller and the lock mechanism being mounted on the unitary assembly. Preferably, the unitary assembly is removably mounted on the lid.
In accordance with one embodiment of the pressure cooker of the present invention, when the controller has moved the lock mechanism into the at least one unlocking position, the controller prevents the pressure indicator from moving out of the second position and when the controller has moved the lock mechanism into the at least one locking position, the pressure indicator is free to move into the first position and the lock mechanism is thereby restrained in the at least one locking position.
In accordance with another embodiment of the pressure cooker of the present invention, the controller includes a selector knob, and a lever operable by the selector knob, the lever including an end portion, the end portion of the lever movable by means of the selector knob to move the lock mechanism between the at least one unlocking position and the at least one locking position and to lock the pressure indicator in the second position. Preferably, the lock mechanism comprises a pin translatable with respect to the pan between a first upper vertical position and a second lower vertical position, the end portion of the lever comprising a helical shape for cooperating with the pin to move the pin between the first and second vertical positions.
In accordance with another embodiment of the pressure cooker of the present invention, the end portion of the lever covers the pressure indictor to lock the pressure indicator in the second position and is movable to uncover the pressure indicator in a position adjacent to the pressure indicator enabling the pressure indicator to move into the first position whereby the end portion of the lever is locked against the pressure indicator.
In accordance with another embodiment of the pressure cooker of the present invention, the pressure cooker includes a rated operating valve for setting the rating of the pressure cooker by compression thereagainst, the selector knob being operable to cause the controller to set the rating. Preferably, the selector knob includes a cam profile for moving the rated operating valve between at least two positions. In a preferred embodiment, the at least two positions correspond to the locking mechanism being in the at least one locking position, the at least two positions including a first position wherein the rated operating valve is released from any resilient compression and a second position wherein the rated operating valve is subjected to a first compression representing a first rated value. Preferably, the at least two positions includes a third position, wherein the rated operating valve is subjected to a second compression representing a second rated value.
The objects of the present invention are thus achieved by a safety device for a pressure cooking appliance with bayonet closure and comprising:
a pan having pan ramps;
a lid having lid ramps;
rotary abutment means for preventing the lid from rotating relative to the pan, placed so that in the closed position the lid ramps engage the pan ramps, the lid and the pan then being prevented from rotating in the direction of rotation that corresponds to closing the appliance;
locking means for locking the lid relative to the pan, the locking means being mounted to move on the appliance under drive from control means suitable for being actuated by the user between at least one unlocking position enabling the appliance to be opened and at least one locking position in which relative rotation between the pan and the lid is prevented; and
a pressure indicator mounted to move freely on the lid between a high, leakproof position and a low, leakage position, depending on the pressure that exists within the appliance, and wherein the pressure indicator, the control means, and the locking means form part of a unitary assembly that is mounted on the lid and that is independent of the handles of the cooking appliance.